<script type="module">
	{
		for (let index of ['a', 'b'].keys()) {
			document.write(`返回键名：${index}<br></br>`);
		}
		
		for (let index of ['a', 'b'].values()) {
			document.write(`返回键值：${index}<br></br>`);
		}
		
		for (let [index, elem] of ['a', 'b'].entries()) {
			document.write(`返回键值对：${index} : ${elem}<br></br>`);
		}
	}
</script>